Angiogenesis is a fundamental process by means of which new blood vessels are formed. This process is essential in multiple normal physiological phenomena such as reproduction, development and even cicatrization. In these normal biological phenomena, angiogenesis is under strict control, i.e., it is triggered during a short period (several days) and then completely inhibited. However, many pathologies are linked to uncontrolled, invasive angiogenesis: arthritis, a pathology due to the damaging of cartilage by invasive neovessels; diabetic retinopathy or the invasion of the retina by neovessels leading to blindness of patients; neovascularization of the ocular apparatus which is a major cause of blindness. This neovascularization is involved in about twenty different eye diseases. Moreover, the growth and metastasis of tumors which are linked directly to neovascularization are dependent on angiogenesis. The tumor stimulates the growth of neovessels by its own growth. Moreover, these neovessels are escape routes for tumors which thereby join up with the blood circulation and induce metastases in sites remote from the initial tumor focus, such as the liver, lungs or bones.
Angiogenesis, the formation of neovessels by endothelial cells, involves the migration, growth and differentiation of endothelial cells. Regulation of these biological phenomena is directly linked to genetic expression.